NEW YORK -- Amazon has started shipping the larger version of its Kindle Fire HD tablet computer on Thursday, five days ahead of schedule.

Amazon is short on stock, though, so new orders won't ship until Dec. 3. Amazon.com Inc. had been taking orders for shipment on Nov. 20.

The Kindle Fire is one of several tablets challenging Apple's (AAPL) iPad.

The tablet, which has an 8.9-inch screen measured diagonally, is available on Amazon's website for $299. The tablet will be available at Best Buy stores beginning Friday and at more retailers in the coming weeks.

A version with cellular access is available for $499 and will start shipping next week as planned, though new orders won't ship until Dec. 3.

The smaller version, which has a 7-inch screen, has been available since September.